As a power transmitting device of a hybrid vehicle including an engine and a motor as power source, for example, Imaeda et al. (“Hybrid System for mini-van 4WD”, Society of Automotive Engineers of Japan, Paper Number 20024219, May 2002, No. 06-02, pp 8-14), especially, FIG. 9 and Table 3, describe one having a double pinion planetary gear unit and three multiplate wet clutches. According to the techniques disclosed by Imaeda et al., the three multiplate wet clutches are operated to perform drive-power switching between the engine and the motor.